Recently, navigation systems based on global positioning system (GPS) technology were developed for use in an automobile. Such navigation systems are capable of receiving signals from a constellation of satellites which is part of the GPS. Based on the received signals, one such navigation system identifies the automobile's location, e.g., in latitude and longitude. The navigation system also detects the automobile's speed and direction. With geographic information stored in an on-board computer in the automobile, the navigation system is capable of audio-visually communicating to a user instructions for reaching a given destination.
Similarly, a GPS navigation device in hand-held form enables a user carrying the device to monitor his/her planned route leading to a given destination. Nowadays, in general, hand-held devices for information organization and communications are popular and have been proliferating. For example, use of cellular phones for communications is ubiquitous. Use of personal data assistants (PDAs), e.g., PALM type hand-held devices, is equally ubiquitous for organizing personal information including meeting schedules, telephone listing, address information, etc. More recently, hand-held communicators emerged which have cellular communication and modem facilities integrated into a PDA, thereby enabling a user to communicate data in a wireless manner, e.g., to send and receive email, and to upload and download information from websites via the Internet.